The Influence of Electromagnetic Vibration on the Microstructure and Corrosion Behavior of Incoloy 825 Superalloy Weld Metal

In this study, the microstructure and corrosion behavior of Incoloy 825 superalloy weld joints were investigated. All the weld joints were produced by GTAW process with simultaneous applying of electromagnetic vibration under the voltages 0-30 Volts the microstructure of the base and weld metals in different welding conditions using optical and scanning electron microscopy was investigated. The corrosion behavior of weld metal using the cyclic polarization test was evaluated. Microscopic images were shown that the weld metals having a fully austenitic matrix contain fine precipitations on the grain boundaries and inside the grains. Increasing the applied vibration intensity causes decreased the distance between dendrites arms and augmentation of fine equiaxed dendrites and the refined grains in the weld metal. Furthermore, it was found that the vibration led to better distribution and refining precipitations in weld metal. The corrosion test results showed that employing electromagnetic vibration improves resistance to corrosion. The least resistance to corrosion (Epit-Ecor) was 555.04 mV, which was related to the No-vibration welded joints, and the most resistance to corrosion was 1025.91 mV that was related to vibrated weld metal with 30 V.